Antenna for cordless phone
in [Design]
|
From: tm on 17 May 2010 14:33 "D Yuniskis" <not.going.to.be(a)seen.com> wrote in message news:hss1ak$m7j$2(a)speranza.aioe.org... > Hi TOm, > > tm wrote: >> "D Yuniskis" <not.going.to.be(a)seen.com> wrote in message >>>>> I've toyed with the idea of adding an external antenna to >>>>> the base unit (which currently just sits on a countertop) >>>>> to try to improve on that. >>>>> >>>>> I rescued a "dual band" antenna kit (AllTel) for a cell phone. >>>>> But, I suspect these operate on a different frequency than >>>>> my "cordless" (902-928MHz)? (sorry, I know *nothing* about >>>>> cell phones -- thankfully! :> ) > >>> No. Antenna will be located in almost the exact center of the >>> area to be covered. I.e., "walking around the neighborhood" >>> (my "walk" is just about 2 miles total -- the furthest point >>> being about 0.55 mi from the "base"). >>> >>>> You can design an antenna that will give you a pattern like a fig. of >>>> an heart, a figure of eight or a very directional antenna. The >>>> directionality will depend on the number of elements. >>>> Ideally you build 2 antennae of the same type and use one for one unit >>>> and the other for the other unit. >>> The "remote" is a handheld device. Impractical to change the >>> antenna on it. >>> >>> The antenna that I was *questioning* will (physically) >>> mate to a Linksys wireless router (though not intended >>> to do so, "just coincidence" -- sorry, I don't deal with >>> RF stuff so i can't tell you what sort of connectors >>> they are -- I don't think they will mate with the >>> base unit on the phone :<) >>> >>> This is similar to what the manufacturer suggests for >>> an external antenna: >>> http://www.sn900.com/graphic/extant20.jpg >> >> Move the base unit to as high a position as possible, maybe into your >> attic if you have one. > > No attics here. :-/ I was hoping to run *an* antenna > (on a length of coax) from the base up to a "high(er) spot". > Nervous about the roof due to lightning, etc. Maybe you could put the base unit in a weather proof container on the roof? At least as a test. The mere fact of getting the antenna outside should be a help. You need to watch running coax as it will have a loss at 900 MHz. Use as large a cable as you can find connectors for and keep the run short, say 10 feet or so. The antenna you linked to will have some gain and that will help. Tom
From: John on 17 May 2010 14:38 On Mon, 17 May 2010 10:23:35 -0700, D Yuniskis <not.going.to.be(a)seen.com> wrote: >Hi John, > >John wrote: >> On Sun, 16 May 2010 10:28:24 -0700, D Yuniskis >> <not.going.to.be(a)seen.com> wrote: >>> >>> Sometimes (rarely), on my "evening sabbatical", I carry >>> a cordless phone (NOT a cell phone) with me. This has >>> sufficient range to cover almost the entire "development" >>> (e.g., I can get about half a mile, as the crow flies). >>> >>> *But*, there is one section (0.52 miles? :> ) where I >>> lose reception. >>> >>> I've toyed with the idea of adding an external antenna to >>> the base unit (which currently just sits on a countertop) >>> to try to improve on that. >>> >>> I rescued a "dual band" antenna kit (AllTel) for a cell phone. >>> But, I suspect these operate on a different frequency than >>> my "cordless" (902-928MHz)? (sorry, I know *nothing* about >>> cell phones -- thankfully! :> ) >> >> Contrary to the popular believe antennae do not increase the >> transmitting power. They change the transmitting power from some >> directions into other directions. > >Correct. I'm not expecting to "boost" the Tx power. >But, rather, get it someplace from which it is easier >for me (at the remote end) to pick it up (likewise, >for the base to pick up my *remote* signal!) > >> You probably are not interested in sending signal to the moon so >> rather then wasting that signal change it to the horizontal plane. >> First you must you must establish the horizontal area that you want to >> cover and if your transmitter is at the end of the terrain you may >> design a small Yagi like the type used to receive TV. > >No. Antenna will be located in almost the exact center of the >area to be covered. I.e., "walking around the neighborhood" >(my "walk" is just about 2 miles total -- the furthest point >being about 0.55 mi from the "base"). > >> You can design an antenna that will give you a pattern like a fig. of >> an heart, a figure of eight or a very directional antenna. The >> directionality will depend on the number of elements. >> Ideally you build 2 antennae of the same type and use one for one unit >> and the other for the other unit. > >The "remote" is a handheld device. Impractical to change the >antenna on it. > >> Coupling to the base unit is another problem. Not easy. >> Describe, please the area you want to cover if you want to make a >> project out of it. I can help. > >The neighborhood is roughly: > >(view in fixed width font) > >+-----+ >| | >| | >| | >| | >| | >| | >| +------------+ >| | >| X | >| | >+------------------+ > >This is *roughly* to scale. The "base" is located at X. >The area is residential in nature so there are houses >filling the region. The top of the illustration is >at a higher elevation than the bottom -- maybe 60 ft? > >There are no commercial establishments in the area. >Most of the construction is masonary. No dense >foliage. > >The problem area (reception) is at the upper left (and >the bottom right) -- no doubt as there are the most >"obstructions" along the sight line. > >I'll drag out a GPS and get some actual measurements, >if necessary. I've not done an exhaustive survey >of where things work/don't work. Though I have found >the upper left corner to be a problem area as I am >often passing through there when I lose signal. > >The antenna that I was *questioning* will (physically) >mate to a Linksys wireless router (though not intended >to do so, "just coincidence" -- sorry, I don't deal with >RF stuff so i can't tell you what sort of connectors >they are -- I don't think they will mate with the >base unit on the phone :<) > >This is similar to what the manufacturer suggests for >an external antenna: > >http://www.sn900.com/graphic/extant20.jpg > >Any pointers appreciated! (RF is BFM!) > >Thx, >--don Don Since you are interested on increasing the signal at 2 areas that are at opposite sides but not in line, a directional antenna is not a solution. The best is probably a vertical whip like the one you show, designed to operating at your frequency. The standard impedance of an antennae designed to be connected to a cable have usually an operating impedance of 50 Ohms at that frequency. This is important because the impedance changes with the frequency and for optimum power transfer the antenna, the cable and the output stage of your transmitter must be of similar impedance at that operating frequency. The cable usually sold for TV is 75 Ohms and you want 50 Ohms if the antenna was design for that impedance at your operating frequency. One of the bands used on Cell phones is on the 900 MH band make sure the one you get is for that band and not for the 1800 band. Propagation of UHF and higher frequencies usually required line of site but are easly reflected by the obstacles they can't penetrate. Installing the antenna outside as high as possible is essential for a reliable link. The solution to your problem adopted by a communication company, would be what I have suggested and if that would' work they would install repeaters. Regards John
From: mpm on 17 May 2010 16:43 On May 17, 11:52 am, John <Y...(a)you.com> wrote: > On Sun, 16 May 2010 10:28:24 -0700, D Yuniskis > > > > > > <not.going.to...(a)seen.com> wrote: > >Hi, > > >Sometimes (rarely), on my "evening sabbatical", I carry > >a cordless phone (NOT a cell phone) with me. This has > >sufficient range to cover almost the entire "development" > >(e.g., I can get about half a mile, as the crow flies). > > >*But*, there is one section (0.52 miles? :> ) where I > >lose reception. > > >I've toyed with the idea of adding an external antenna to > >the base unit (which currently just sits on a countertop) > >to try to improve on that. > > >I rescued a "dual band" antenna kit (AllTel) for a cell phone. > >But, I suspect these operate on a different frequency than > >my "cordless" (902-928MHz)? (sorry, I know *nothing* about > >cell phones -- thankfully! :> ) > > Contrary to the popular believe antennae do not increase the > transmitting power. They change the transmitting power from some > directions into other directions. > You probably are not interested in sending signal to the moon so > rather then wasting that signal change it to the horizontal plane. > First you must you must establish the horizontal area that you want to > cover and if your transmitter is at the end of the terrain you may > design a small Yagi like the type used to receive TV. > You can design an antenna that will give you a pattern like a fig. of > an heart, a figure of eight or a very directional antenna. The > directionality will depend on the number of elements. > Ideally you build 2 antennae of the same type and use one for one unit > and the other for the other unit. > Coupling to the base unit is another problem. Not easy. > Describe, please the area you want to cover if you want to make a > project out of it. I can help. > > John- Hide quoted text - > > - Show quoted text - Here in the US, it's "antenna" and "antennas". You'll find antennae on bugs and cockroaches. :) Sorry, that's just a pet peeve. Telecom attorneys make the same mistake all the time! Also, if in the US, FCC rules prohibit you from monkeying around with the antennas. Legally speaking, if in the US, you'll just have to live with it, or select an alternate technology / device. -mpm
From: mpm on 17 May 2010 16:46 On May 17, 12:23 pm, D Yuniskis <not.going.to...(a)seen.com> wrote: > Hi John, > > > > > > John wrote: > > On Sun, 16 May 2010 10:28:24 -0700, D Yuniskis > > <not.going.to...(a)seen.com> wrote: > > >> Sometimes (rarely), on my "evening sabbatical", I carry > >> a cordless phone (NOT a cell phone) with me. This has > >> sufficient range to cover almost the entire "development" > >> (e.g., I can get about half a mile, as the crow flies). > > >> *But*, there is one section (0.52 miles? :> ) where I > >> lose reception. > > >> I've toyed with the idea of adding an external antenna to > >> the base unit (which currently just sits on a countertop) > >> to try to improve on that. > > >> I rescued a "dual band" antenna kit (AllTel) for a cell phone. > >> But, I suspect these operate on a different frequency than > >> my "cordless" (902-928MHz)? (sorry, I know *nothing* about > >> cell phones -- thankfully! :> ) > > > Contrary to the popular believe antennae do not increase the > > transmitting power. They change the transmitting power from some > > directions into other directions. > > Correct. I'm not expecting to "boost" the Tx power. > But, rather, get it someplace from which it is easier > for me (at the remote end) to pick it up (likewise, > for the base to pick up my *remote* signal!) > > > You probably are not interested in sending signal to the moon so > > rather then wasting that signal change it to the horizontal plane. > > First you must you must establish the horizontal area that you want to > > cover and if your transmitter is at the end of the terrain you may > > design a small Yagi like the type used to receive TV. > > No. Antenna will be located in almost the exact center of the > area to be covered. I.e., "walking around the neighborhood" > (my "walk" is just about 2 miles total -- the furthest point > being about 0.55 mi from the "base"). > > > You can design an antenna that will give you a pattern like a fig. of > > an heart, a figure of eight or a very directional antenna. The > > directionality will depend on the number of elements. > > Ideally you build 2 antennae of the same type and use one for one unit > > and the other for the other unit. > > The "remote" is a handheld device. Impractical to change the > antenna on it. > > > Coupling to the base unit is another problem. Not easy. > > Describe, please the area you want to cover if you want to make a > > project out of it. I can help. > > The neighborhood is roughly: > > (view in fixed width font) > > +-----+ > | | > | | > | | > | | > | | > | | > | +------------+ > | | > | X | > | | > +------------------+ > > This is *roughly* to scale. The "base" is located at X. > The area is residential in nature so there are houses > filling the region. The top of the illustration is > at a higher elevation than the bottom -- maybe 60 ft? > > There are no commercial establishments in the area. > Most of the construction is masonary. No dense > foliage. > > The problem area (reception) is at the upper left (and > the bottom right) -- no doubt as there are the most > "obstructions" along the sight line. > > I'll drag out a GPS and get some actual measurements, > if necessary. I've not done an exhaustive survey > of where things work/don't work. Though I have found > the upper left corner to be a problem area as I am > often passing through there when I lose signal. > > The antenna that I was *questioning* will (physically) > mate to a Linksys wireless router (though not intended > to do so, "just coincidence" -- sorry, I don't deal with > RF stuff so i can't tell you what sort of connectors > they are -- I don't think they will mate with the > base unit on the phone :<) > > This is similar to what the manufacturer suggests for > an external antenna: > > http://www.sn900.com/graphic/extant20.jpg > > Any pointers appreciated! (RF is BFM!) > > Thx, > --don- Hide quoted text - > > - Show quoted text - If you are in the US or Canada, flip the base unit over. You should see a tag with the FCC ID number on it. What is that number?
From: Joerg on 17 May 2010 17:15
mpm wrote: > On May 17, 11:52 am, John <Y...(a)you.com> wrote: >> On Sun, 16 May 2010 10:28:24 -0700, D Yuniskis >> >> >> >> >> >> <not.going.to...(a)seen.com> wrote: >>> Hi, >>> Sometimes (rarely), on my "evening sabbatical", I carry >>> a cordless phone (NOT a cell phone) with me. This has >>> sufficient range to cover almost the entire "development" >>> (e.g., I can get about half a mile, as the crow flies). >>> *But*, there is one section (0.52 miles? :> ) where I >>> lose reception. >>> I've toyed with the idea of adding an external antenna to >>> the base unit (which currently just sits on a countertop) >>> to try to improve on that. >>> I rescued a "dual band" antenna kit (AllTel) for a cell phone. >>> But, I suspect these operate on a different frequency than >>> my "cordless" (902-928MHz)? (sorry, I know *nothing* about >>> cell phones -- thankfully! :> ) >> Contrary to the popular believe antennae do not increase the >> transmitting power. They change the transmitting power from some >> directions into other directions. >> You probably are not interested in sending signal to the moon so >> rather then wasting that signal change it to the horizontal plane. >> First you must you must establish the horizontal area that you want to >> cover and if your transmitter is at the end of the terrain you may >> design a small Yagi like the type used to receive TV. >> You can design an antenna that will give you a pattern like a fig. of >> an heart, a figure of eight or a very directional antenna. The >> directionality will depend on the number of elements. >> Ideally you build 2 antennae of the same type and use one for one unit >> and the other for the other unit. >> Coupling to the base unit is another problem. Not easy. >> Describe, please the area you want to cover if you want to make a >> project out of it. I can help. >> >> John- Hide quoted text - >> >> - Show quoted text - > > Here in the US, it's "antenna" and "antennas". In California its "antena" and "antenas". Para mejorar la recepcion :-) -- SCNR, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |